The invention relates to a fabric reinforcement for a hose structure.
It has been known that hose structures of numerous varieties can be reinforced by layers of various fabrics. For example, the Robinson et al. U.S. Pat. No. 3,506,515 shows a hose which is reinforced by a fabric. However, it is noted that orientation of the yarns within the fabric is such that the filling yarns are perpendicular to the warp yarns of the fabric.
The Lister U.S. Pat. No. 1,469,519 shows a fabric layer similar to that of Robinson et al. and an additional layer having cords displaced in a diagonal direction with respect to the yarns of the first layer.
Reinforcing fabric layers are of particular importance in railroad air brake hose. Railroad air brake hose fabric has been made by using spun fabrics from natural and synthetic fiber. In order to maintain high strengths, these heavy fabrics have been tightly woven then calender coated with polymer, bias cut and wrapped around a mandrel and tube to form air brake hose.
By specification and design three or more layers of fabric that has been bias cut to 45.degree. have been used to maintain burst strength and pass rigid railroad specifications. The use of bias cut fabric allows for hose flexibility and helps to resist buckling or kinking of the hose.
As a practical matter, hose manufacturers often acquire prefabricated fabrics for reinforcing hose from fabric manufacturers. For example, a hose manufacturer who might wish to modernize his hose building units, might require continuous rolls of 45.degree. angle bias cut fabrics that have been impregnated with polymer and slit to a width convenient to cover the hose mandrels, give proper strength, and flex properties.
Despite the advantages of using bias cut fabrics in the reinforcement of railroad air brake hose, there remains a need in the art to develop a fabric reinforcement which will more readily enable the rigid railroad specifications to be met. Therefore, there is a need in the art to develop improved fabric reinforcements for hose structures.